Method of treating cellulose nitrate and the formation of cellulose compounds



Patented July '7, 1925.

UNITED 'S 'I I-VFES' JOHN COLL NS CLANGY, or PROVIDENCE, RHODE ISLAND, AssIeNoa TO THE NITRO v p GEN CORPORATION, OF :QBOVIDENCE, RHODE ISLAND, A CORPORATION OF ISLAND.

.METHOD or TREATING :CELLULQSE NITRATE AND 'rnu FORMATION or cELLULOsE- 1,544,812 PATENT QFFICE.

RHODE comrouNDs.

Nollllrawing. Original application filed July 2, 1921, Serial No. 482,173. 'Dlvided and this application filed February 27, 1922. Serial 1T0. 539,718.

To all whom it may concem: I

Be it l'rnown that 1, JOHN GoLLINs CLANOY, a subject of the King of Great Britain, residing at Providence, in the county of Providence and $tate of Rhode Island, have invented certain new and useful Improvements in-Methods'ofTreat-in Cellulose Ni trateand the Formation of 61111108600111- pounds, of which the following is a specification.

This invention relates to an improved method Oftreating cellulose nitrate and the formation ofcellulose compounds, and has to do more particularlywith the use of an improved solvent forcellulose esters and the formation'through the i'nstrumentality of said solventof a cellulose compound pos- I sessing certain new and useful roperties by reason of which it is capable 0 wide use in the arts. a j

While it is known that certain cellulose esters, such for, example, as certain of the acetates and nitrates,- -are soluble in certain substances such as acetone, amyl acetate, tetrachlorethane and carbon bisulfid, the use of these substances as well as other solvents ordinarily employed for this purpose is open to. certain objections such as the cost of the.

resultant; pr 5 solvents, their inflamm'ability, their poisonous nature and the difficulty experienced in removing, the solvent from the final products.

Moreover, by no means all of the cellu lose esters are soluble inany of-the solvents named, and each of the above solvents is adapted for use with onl an extremely limited nu ber of the cel ulose esters included in t e classes mentioned above.

One object of the present invention is to rovide a novel form of solvent for cellulbse esters includin particularly the acetates and nitrates, w' 'ch is capable ofmore general usethan those now employed, which is capableof'being readily used without the exercise of the care necessary in connection with some of those previously employed,

which is not inflammable and which is ca-.

pable of' bein readily separated from the uct. Another object of the invention is to provide a novel method oftreatment for cellulose esters whereby they may be readily moniaser'vesflas an exce dissolved and the cellulose compounds easily recovered from the, solution and formed into materials 'having extensive use in the arts, such, for example, as artificial silk, photo graphic films, etc.

A further object of the invention is to provide --a new composition ofmatter capable of extensive use and having certain novel characteristics not enerally possessed by the materials formed rom methods heretofore employed.

Other objects and advantages of the invention relate to certain novel steps and combinations of steps involved in themanu factore of the material 'as well as certam, methods of combining the materials em-. ployed as will be more fully set forth in the mit it to be readily removed: fromthece lu-- lose com oundwby evaporation. By the use of liqui anhydrous ammonia cellulose acetates andnitrates can be. dissolved so as to continue to ossess the structure of the" original cellu ose acetates and nitrates 'Wlth-. out beingdegraded, that is, without losing their structuralaggregates, thus formin a cellulose compoundwhich can be shape desired form and still retain [the 1 inherent in the original cellulose into an strengt structure.

1 I p opose to place the cellulose esters, such for example ascellulose acetates, in a bath of liquid anhydrous ammonia, whereupon I find that they immediately dissolve to form a clear'solutlon which can be readily freed 'froin air bubbles or entrained gases, and the Solution thus ,itormed ma then be caused to flow upon an endless belt, forced through minute apertures or laced in moulds and the ammonia freed groin the solution by eyaporation to form' a transparentor translucent-film, thread or other desired shape possessin a, high degree of strength and ca ble 0 use foravarietyof purposes.

111cc anhydrous ammonia is liquefied normally .only at comparatively low. temperatures unless subjected. to pressure in excessof that exerted by the atmosphere Ifprefor to e set the solution of the cellulose es- ,ters in the liquid anhydrous ammonia under.

a pressure somewhat greater than that nonsufliciently loweri-n mally exerted the atmosphere and to evaporate OR the ammonia from the resul tant product by lowering'the pressure be-' low that at which the solution is efl'ected.

However, theuanhydrous ammonia may be liquefied at normal atmospheric pressure by its temperature when it may be employe to dissolvethe cellulose esters as above described and the ammonia substantially entirely removed by evaporation. In removingthe ammonia from the cellulosecompcund in solution, the step'of eva crating off' the ammonia may be carried out under a pressure somewhat less than that norm'ally exerted by the atmosphere if desired, in order to hasten the process. I prefer'to efiect the removal of.

the ammonia in anoatmosphere from which moisture has been excluded so far as practicable in order to prevent the formation of bubbles in the cellulose compoundand thus obtain a more uniform and high grade prodnot. The ammonia used asa solvent can, of

course, be readily recovered;

Having foundthat the nitrates of cellulose as well as the acetates" are'soluble in liquid anhydrous ammonia as above described, I may utilize liquid anhydrous ammonia for dissolving either cellulose acetates or cellulose nitrates se arately or may mix cellulose acetates and ac lulose nitrates in any desired proportions and dissolve the mix-f ture in ammonia to obtain a cellulose compo- 81131011 possessing certam desired qualities when the solvent has been removed.

The product resulting from the treatment of cellulose esters as above described pos-- sesses certain advantages over similar: prod uctsfheretofore formed by dissolving cellulose esters in the solvents previousl used, by reason of the 'fact that the liqui anhydrous ammonia may be substantially entirely removed from the compound, whereas it has been practically impossible to entirely eliminate the solvents previously used from the resultant product. Moreover, the fact, that the liquid anhydrous ammonia more readily dissolves certain of the cellulose esters not heretofore readily soluble in the solvents previously known imparts to the resultant product, by reason of the inclusion of such esters therein a structural strength not heretoforewpossible b the methods of treatment previously-'emp 0 ed.

v As one illustration of an Important application of myinvention, photogra hic films as now used'are-tormed from cellu ose esters and contaln, when completed, silver salts and gelatine compounds. At the present p forme time these films are generally hurned' after use to recover the silver deposited therein, while by the use of my improved method the cellulose esters of the film, may be readlly dissolved thus permitting the recovery of the cellulose for, againforminga filmhand at the same time recovering the metallic silver and by the ammonia.

This case is a division of my application ,gelatine compounds which are not acted upon Serial No. 4 82,l73' filed July2, 1921, for a: 1 method of itreating cellulose and the 'formation of cellulose compounds.

What I claim is:

1. The process ,oftreating cellulosenitra te with liquid anh drous ammonia to dissolve the same-and then "substantiallyfremovin 2. The process of treating cellulose nitra t e the ammonia from the. substance with liquid anhydrous ammonia to dissolve the sameand then substantially removing the ammonia therefrom under a pressure .less'than that under'which the solution was effected;

3. The process of treating cellulose nitrate with liquid anhydrous ammonia to dissolve the same and' then substantially removing the ammonia therefrom with exclusion of moisture. j

I 4. The process which comprises subject ing cellulose nitrate to the action of --liquid anhydrous ammonia.

5. The process which comprises subjecting cellulose nitrate totheac'tion of liquid anhydrous ammonia under super-atmospheric pressure. A v

6. The process which comprises subjecting cellulose nitrate to the action of liquid anhydrous ammonia under super-atmospheric pressure, and subsequently evaporating ofi the ammonia.

7..The process which comprises, treating K cellulose nitrate with liquid anhydrous'am monia'and then substantially removing the liquid anhydrous'ammonia from the mass ,pound' which comprises, subjecting cellulose nitrate to the action of liquid anhydrous ammonia, and then substantially removing the ammonia therefrom under a pressure less than that at which the cellulose nitrate was. subjected to the actionofthe ammonia.

In testimony whereof I have afiixed my signature. 7

. JOHN COLLINS QLANCY. 

